Fits Filters from 2 1/2" to 3 1/8". Removes all oil filters from 2 1/2" to 3 1/8" in diameter. This extra large range enables the 63600 wrench to fit most all import car filters plus the common 3" domestic car filters. Steel jaws grip filter without slipping. Works in tight spots from the front of the filter using 3/8" drive. The wrench has a spring to pull the jaws in. As you turn the wrench with the square drive it keeps tightening tighter. It will only remove the filter. You can't use it to install a filter. per MW